Do the androids they they sell on this site have the same stuff as normal androids? Because these androids are from different chinese companies which i have never heard of...
Just make sure that it is able to access the actual Android Market. As an example, Archos brand tablets have their own Archos market. However, you can install an app that allows them to access the Android market. If you can access the Android market, you have access to all of the Android apps.
Then, the only danger is the same thing that someone posted earlier. Make sure that the phone is able to upgrade to the most recent version of the Android OS.